122 resultados para Acartia danae, c2, length


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This article describes the design of a new type of long-path-length thin-layer cell (LPTLC), which is constructed by inserting two Teflon cell bodies into a standard cuvette. This cuvette holder enables the LPTLC to combine with photometric instrumentation conveniently. Gold, platinum, glassy carbon, and other materials can be used for the working electrode. Since no soluble adhesive material is used, the cell can meet various needs (in situ conventional and derivative W-vis, in situ circular dichroism, etc.) in both aqueous and nonaqueous systems.

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The adsorption of cationic surfactant cetylpyridinium bromide (CPB) on a glassy carbon (GC) electrode surface has been studied by spectroelectrochemistry with a long optical path length thin-layer cell (LOPTLC) for the first time. A fine adsorption isotherm of CPB molecules from an aqueous solution containing 0.10 M KBr has been obtained over the range of (1.00-8.00) x 10(-5) M. From theoretical calculation and experimental data, adsorption of CPB on the GC electrode surface shows four distinct orientations and three large orientation transitions. Compared with the ordinary isotherm, the differential isotherm is more characteristic and would be suitable for the study of orientation transitions of organic compounds. With a theoretical treatment of the adsorption isotherm, four orientations of adsorbed CPB on a GC electrode surface coincide with the Frumkin-Langmuir type. From adsorption parameters the Frumkin-Langmuir equations, the adsorption free energy and, therefore, the equilibrium constants of orientation transitions of the CPB molecule can be obtained.

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In this paper, the electric dichroism of cetylpyridinium bromide (CPB) has been found and studied by spectroelectrochemistry with a long optical path length thin-layer cell (LOPTLC) for the first time. The CPB molecule with a long carbon chain and a polar pyridinium ring is anisotropic in molecular configuration or in polarizability. In the electric field of a thin-layer cell, the CPB molecule reorientates along the direction of the electric field and exhibits electric dichroism, which results in the increase of absorbance of CPB in the UV-vis range. By use of in situ measurement of spectroelectrochemistry, the order parameters of long molecular axis (S = 0.845) and short molecular axis (D = 0.155) and the angle between the long axis direction of the CPB molecule and the direction normal to the electrode surface (theta = 18-degrees 44') have been determined. These data were used to describe the state of arrangement of the molecules in the solution. The reorientation of CPB molecules is the result of the interaction between the anisotropic molecules and electric field. The effects of the concentration of CPB and of the applied electric field on the electric dichroism have been investigated.

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To establish a molecular-marker-assisted system of breeding and genetic study for Laminaria japonica Aresch., amplified fragment length polymorphism (AFLP) was used to construct a genetic linkage map of L. japonica featuring 230 progeny of F-2 cross population. Eighteen primer combinations produced 370 polymorphic loci and 215 polymorphic loci segregated in a 3:1 Mendelian segregation ratio (P <= 0.05). Of the 215 segregated loci, 142 were ordered into 27 linkage groups. The length of the linkage groups ranged from 6.7 to 90.3 centimorgans (cM) with an average length of 49.6 cM, and the total length was 1,085.8 cM, which covered 68.4% of the estimated 1,586.9 cM genome. The number of mapped markers on each linkage group ranged from 2 to 12, averaging 5.3 markers per group. The average density of the markers was 1 per 9.4 cM. Based on the marker density and the resolution of the map, the constructed linkage map can satisfy the need for quantitative trait locus (QTL) location and molecular-marker-assisted breeding for Laminaria.

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The haploid stage of gametophytes of the subtidal brown alga Undaria pinnatifida can be vegetatively propagated under favorable conditions. This unique characteristic makes it possible to establish independent gametophyte cell lines that are zoospore-derived. Sporophytic offspring can be generated through hybridizing the male and female gametophytes, which are derived from different cell lines. Accumulated experiences in this and other species in Laminariales demonstrated the applicability of this novel way to breed desired strains for open-sea cultivation. Sporophytic offspring originated from mono-crossing of male and female gametophyte clones were shown to have similar morphological characteristics under identical ambient conditions. However, there has been no report to relate this similarity on molecular levels. In this report, amplified fragment length polymorphism (AFLP) and microsatellite markers were used to analyze the genetic identity of sporophytic offspring of U. pinnatifida originated from two mono-crossing lines (M1 and M2), two self-breeding lines (S1 and S2) and one wild population (W). Totally 318 AFLP loci were revealed by use of 11 primer sets, of which 4.7%, 0.3%, 17.9%, 16.4% and 36.5% were polymorphic in M1, M2, S1, S2 and W, respectively. The pairwise genetic identity among the individuals of the same line was assessed. It was shown that offspring from mono-crossing lines had a higher degree of identity (95.6-100%) than self-breeding lines (87.7-98.4%) and the wild population (81.5-92.1%). Analysis by use of six microsatellite loci also revealed a higher genetic identity among individuals of the mono-crossing line, further confirming the results of AFLP analysis. Results from this investigation support, on molecular levels, the novel way to produce and maintain strains in U. pinnatifida by use of different gametophyte cell lines.

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Transglutaminase can catalyze the cross-linking reaction between soluble clotting protein molecules from the plasma for prevention of excess blood loss from a wound and obstructing micro-organisms from invading the wound in crustaceans. A novel transglutaminase (FcTG) gene was cloned from hemocytes of Chinese shrimp Fenneropenaeus chinensis by 3' and 5' rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA consists of 2972 bp, encoding 757 amino acids with a calculated molecular mass of 84.96 kDa and a theoretical isoelectric point of 5.61. FcTG contains a typical transglutaminase-like homologue (TGc domain: E-value = 1.94e-38). Three catalytic sites (Cys-324, His-391 and Asp-414) are present in this domain. The deduced amino acid sequence of FcTG showed high identity with black tiger shrimp TG, kuruma shrimp TG and crayfish TG. Transcripts of FcTG mRNA were mainly detected in gill, lymphoid organ and hemocytes by RT-PCR. RNA in situ hybridization further confirmed that FcTG was constitutively expressed in hemocytes both in the circulatory system and lymphoid organ. The variation of mRNA transcription level in hemocytes and lymphoid organ following injection of killed bacteria or infection with white spot syndrome virus (WSSV) was quantified by RT-PCR. The up-regulated expression of FcTG in shrimp lymphoid organ following injection of bacteria indicates that it is inducible and might be associated with bacterial challenge. (c) 2006 Elsevier Ltd. All rights reserved.

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In Laminaria japonica Aresch breeding practice, two quantitative traits, frond length (FL) and frond width (FW), are the most important phenotypic selection index. In order to increase the breeding efficiency by integrating phenotypic selection and marker-assisted selection, the first set of QTL controlling the two traits were determined in F-2 family using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Two prominent L. japonicas inbred lines, one with "broad and thin blade" characteristics and another with "long and narrow blade" characteristics, were applied in the hybridization to yield the F-2 mapping population with 92 individuals. A total of 287 AFLP markers and 11 SSR markers were used to construct a L. japonica genetic map. The yielded map was consisted of 28 linkage groups (LG) named LG1 to LG28, spanning 1,811.1 cM with an average interval of 6.7 cM and covering the 82.8% of the estimated genome 2,186.7 cM. While three genome-wide significant QTL were detected on LG1 (two QTL) and LG4 for "FL," explaining in total 42.36% of the phenotypic variance, two QTL were identified on LG3 and LG5 for the trait "FW," accounting for the total of 36.39% of the phenotypic variance. The gene action of these QTL was additive and partially dominant. The yielded linkage map and the detected QTL can provide a tool for further genetic analysis of two traits and be potential for maker-assisted selection in L. japonica breeding.

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C2 domains are protein structural modules found in many eukaryotic proteins involved in signal transduction, membrane trafficking, and immune defense. Most of the studied C2 domain-containing proteins are multi-domained in structure, in which the C2 domain is an independently folded motif and plays an essential role in calcium-dependent membrane-targeting. Although C2 domains isolated from intact proteins have been studied for biological functions, no study on natural proteins containing C2 domain only has been documented. In this study, we identified a Scophthalmus maximus protein SmC2P1 that is comprised of a single C2 domain and lacks any other apparent domain structures. The deduced amino acid sequence of SmC2P1 contains 129 residues and shares 36-38% identities with the C2 domains of the perforins of several fish species. Like typical C2 domains, SmC2P1 is predicted to organize into eight beta-strands with a Ca2+-binding site located in inter-strand loops. SmC2P1 expression was detected, in deceasing order, in liver, spleen, blood, brain, muscle, kidney, gill, and heart. Experimental challenge of turbot with a bacterial pathogen significantly upregulated SmC2P1 expression in kidney in a time-dependent manner. Recombinant SmC2P1 purified from yeast exhibits no hemolytic activity but binds to pathogen-infected kidney lymphocytes in the presence of calcium. Furthermore, interaction of recombinant SmC2P1 with bacterium-infected lymphocytes reduced bacterial survival. These results indicate that SmC2P1 is a functional protein that is involved in host immune defense against bacterial infection. (C) 2010 Elsevier Ltd. All rights reserved.

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With a "two-way pseudo-testcross" mapping strategy, we applied the amplified fragment length polymorphism (AFLP) markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F, cross family (Laminaria longissima Aresch. x L. japonica Miyabe) with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1:1 ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3:1 Mendelian segregation ratio. Among the loci with 1:1 segregating ratios, 79 loci were ordered in 14 linkage groups (648.6 cM) of the paternal map, and 72 loci were ordered in 14 linkage groups (601.9 cM) of the maternal map. The average density of loci was approximately 1 per 8 cM. To investigate the homologies between two parental maps, we used 58 loci segregated 3:1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.

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20世纪90年代以来,为了确保日益增长的人口对蛋白质的需求,海洋鱼类养殖在全球范围内日趋发展。然而,许多养殖鱼类的品质如抗病力、口味等与野生种类相比大为降低。饵料对于鱼类品质的好坏起着至关重要的作用。在海洋的自然环境中,浮游动物,特别是数量庞大、种类繁多的桡足类是野生鱼类的天然活饵料。哪些桡足类适于作养殖饵料,如何获得、从何处获得桡足类,人工培养是否可行,能否通过加入桡足类来改善养殖鱼类的品质是长期以来业内人士一直关注的问题,需要大量的基础性探索研究工作。 开展有潜在开发价值种的生物学特性及室内培养的基础研究,进而开展大量生产技术的研究与应用,不仅是开发利用桡足类的一个重要途径,而且可以获得一些重要的生态学参数。 本论文自2003年10月-2004年9月之间,在胶州湾采集不同的桡足类种类,通过室内比较培养实验,选定双刺纺锤水蚤作为具有开发潜力的研究培养对象,对其展开一系列培养条件及生物学特性研究,在此基础上进行了小水体增殖培养,结合现场调查资料对与其生活策略相关的生态学问题进行了初步研究探索。结果如下: 筛选:2003年10月-2004年9月全年不同季节共采集11 种桡足类,在室内自然温度、自然海水(盐度30-32)下长时间培养,粗略筛选出能够经受实验室人工养殖水体生活的种类有:强额拟哲水蚤(Paracalanus. crassirostris)、汤氏长足水蚤(Calanopia thompson)、太平洋真宽水蚤(Eurytemora pacifica)、双刺纺锤水蚤(Acartia bifilosa)。对上述种类的成体和子代幼体分别测定其对不同盐度、温度的耐受能力。培养结果表明:18℃室温下,强额拟哲水蚤幼体在盐度20以上的环境中,存活时间不超过11天;汤氏长足水蚤雌体在培养温度低于20℃时,只能存活10天;25℃室温下,当盐度低于20时,汤氏长足水蚤雌体存活时间不超过9天,子代的存活时间不超过7天;太平洋真宽水蚤不适宜在温度较高的夏秋季培养,幼体在不同盐度的实验条件下存活时间不超过5天,不适宜长期培养;双刺纺锤水蚤在全年8-24℃的室内培养温度范围内保持了24-85%的存活率,雌体和子代在盐度10-35的范围内都能存活,最终结果表明双刺纺锤水蚤是其中最适宜进行人工培养的种类。 繁殖:对双刺纺锤水蚤雌体的培养条件和繁殖生物学的研究结果表明:在本实验所使用的6种微藻饵料:微绿球藻(Nannochloropsis oculata)、小球藻(Chlorella.sp)、等鞭金藻(Isochrysis galbana)、三角褐指藻(Phaeodactylum tricornutum)、亚心型扁藻(Platymonas subordiformis)、中肋骨条藻(Skeletonema costatum)中,亚心型扁藻和中肋骨条藻适宜成体培养,亚心型扁藻对雌体存活有利,排粪率也要比中肋骨条藻低得多,亚心型扁藻在高温条件下的饵料利用效率要高于中肋骨条藻,中肋骨条藻对产卵有利,二者混合优势互补;预饥饿处理的双刺纺锤水蚤恢复到最高产卵率需要较长的时间,并且一直保持较低的产卵率;该种繁殖的最适温度范围15-20℃;在10-25℃温度范围内的平均产卵率差异并不显著。 生长及发育:对双刺纺锤水蚤幼体培养条件及发育生物学研究结果表明:在本实验所使用的6种微藻饵料中,微绿球藻是比较理想的开口饵料;粒径小( 4 m)的微藻——微绿球藻和小球藻不能保证双刺纺锤水蚤后期无节幼体发育至桡足阶段,22℃以下采用微绿球藻 + 亚心型扁藻 + 中肋骨条藻的食物搭配,22℃以上需加入粒径在4m左右的等鞭金藻。 世代时间:通过一系列的温度梯度实验,证明在相同饵料的情况下,温度对双刺纺锤水蚤的发育具有显著的影响,在15-25℃的范围内,随着温度的升高,生长速度加快、世代周期缩短;在温度条件为15、18、20、22、25℃下的世代时间分别为25.5, 18.5, 13, 11.5, 9.5天。 群体培养:研究了适宜的微藻饵料种类搭配比例以及总饵料浓度对种群日均增值率的影响。结果表明:20℃下培养宜采用亚心型扁藻:中肋骨条藻:微绿球藻按含碳量2:1:1的比例组成混合饵料,达到最高增殖率的混合饵料浓度范围在1.0-4.0 μg C ml-1之间;25℃下培养宜采用亚心型扁藻:中肋骨条藻:微绿球藻:等鞭金藻按含碳量2:1:1:2的比例组成混合饵料,日均增殖率在混合饵料总浓度为1.0 μg C ml-1 时最高,低于和高于此浓度都会降低日增值率。 度夏机制:针对野外大面调查发现双刺纺锤水蚤在高温季节的胶州湾内仍然存在的事实(传统观点认为该种在夏季从水体中消失,通过休眠卵度夏),本论文从基础生态学研究出发,根据胶州湾夏季的温度和叶绿素浓度资料,设计实验研究了高温和饵料浓度对成体繁殖和幼体生长发育的影响。实验发现,饵料浓度对高温下雌体的繁殖有着明显的影响,15g Chla l-1浓度下的雌体在28℃都可以保持产卵状态,而且卵的孵化率也在50%以上;各处理中的卵都很快孵化,并保持了60%以上的孵化率;高浓度组15 g Chla l-1和10 g Chla l-1,无节幼体都能发育至成体,低浓度5 g Chla l-1处理组中,28℃下,不能发育至桡足阶段,而25℃下也只能发育至C4期。在本实验中没有发现双刺纺锤水蚤产生休眠卵。在胶州湾自然环境中发现该种全年存在。胶州湾中的双刺纺锤水蚤在夏季能够在不产生休眠卵的情况下安全度夏。

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The influence of diatoms on the reproduction and naupliar development of Acartia bifilosa was investigated under laboratory conditions, comparing initial in situ values and laboratory-food treatments. Egg production by A. bifilosa was significantly reduced by one diatom diet (Phaeodactylum tricornutum: Pt) and by two non-diatom diets (Platymonas subordiformis: Ps and Nannochloropsis oculata: No). It was less affected by the other diatom diet (Skeletonema costatum: Sc) or by two mixed-food treatments (D-mix and DG-mix), composed of two diatoms (Pt, Sc) and four species (Pt, Sc, Ps and No), respectively. The negative effect of Pt was eliminated when adult copepods were offered mixed-food diets. There were no significant differences between the hatching success values observed in filtered seawater and in algal exudates, indicating that diatoms did not produce active dissolved toxic substances under the different food concentrations tested. The mortality rate of nauplii was higher with Pt than the other diets, suggesting that this diatom species had a negative effect on egg production, hatching success and naupliar survival simultaneously. Compared to other diets, No and Pt were not beneficial food sources for reproduction and for female and larval survival. (c) 2007 Elsevier B.V. All rights reserved.

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Amplified fragment length polymorphisms (AFLP) were used to study the inheritance of shell color in Argopecten irradians. Two scallops, one with orange and the other with white shells, were used as parents to produce four F-1 families by selfing and outcrossing. Eighty-eight progeny, 37 orange and 51 white, were randomly selected from one of the families for segregation and mapping analysis with AFLP and microsatellite markers. Twenty-five AFLP primer pairs were screened, yielding 1138 fragments, among which 148 (13.0%) were polymorphic in two parents and segregated in progeny. Six AFLP markers showed significant (P < 0.05) association with shell color. All six loci were mapped to one linkage group. One of the markers, F1f335, is completely linked to the gene for orange shell, which we designated as Orange1, without any recombination in the progeny we sampled. The marker was amplified in the orange parent and all orange progeny, but absent in the white parent and all the white progeny. The close linkage between F1f335 and Orange1 was validated using bulk segregation analysis in two natural populations, and all our data indicate that F1f335 is specific for the shell color gene, Orange1. The genomic mapping of a shell color gene in bay scallop improves our understanding of shell color inheritance and may contribute to the breeding of molluscs with desired shell colors.

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In an effort to develop genetic markers for oyster identification, we studied length polymorphism in internal transcribed spacers (ITS) between major ribosomal RNA genes in 12 common species of Ostreidae: Crassostrea virginica, C. rhizophorae, C. gigas, C. angulata, C. sikamea, C. ariakensis, C. hongkongensis, Saccostrea echinata, S. glomerata, Ostrea angasi, O. edulis, and O. conchaphila. We designed two pairs of primers and optimized PCR conditions for simultaneous amplification of ITS 1 and ITS2 in a single PCR. Amplification was successful in all 12 species, and PCR products were visualized on high-resolution agarose gels. ITS2 was longer than ITS 1 in all Crassostrea and Saccostrea species, whereas they were about the same size in the three Ostrea species. No intraspecific variation in ITS length was detected. Among species, the length of ITS I and ITS2 was polymorphic and provided unique identification of 8 species or species pairs: C. ariakensis, C. hongkongensis, C. sikamea, O. conchaphila, C. virginica/C. rhizophorae, C. gigas/C. angulata, S. echinata/S. glonzerata, and O. angasi/O. edulis. The ITS assay provides simple, rapid and effective identification of C. ariakensis and several other oyster species. Because the primer sequences are conserved, the ITS assay may be useful in the identification of other bivalve species.